diff --git a/API.md b/API.md
index ebec9d2..bbab501 100644
--- a/API.md
+++ b/API.md
@@ -117,6 +117,8 @@ $ curl -d '{"debian-7-i386":"2","debian-7-x86_64":"1"}' --url vmpooler.company.c
 }
 ```
 
+**NOTE: Returns either all requested VMs or no VMs.**
+
 ##### POST /vm/<pool>
 
 Check-out a VM or VMs.
@@ -156,6 +158,8 @@ $ curl -d --url vmpooler.company.com/api/v1/vm/debian-7-i386+debian-7-i386+debia
 }
 ```
 
+**NOTE: Returns either all requested VMs or no VMs.**
+
 ##### GET /vm/<hostname>
 
 Query a checked-out VM.